perf: add functions to get vfs-like object for Mercurial earlier than 2.3
Before this patch, using svfs prevents perf.py from measuring
performance of Mercurial earlier than 2.3 (or
7034365089bf), because
svfs isn't available in such Mercurial, even though there are some
code paths for Mercurial earlier than 2.3 in perf.py.
For example, setting "_prereadsize" attribute in perfindex() and
perfnodelookup() is effective only with hg earlier than 1.8 (or
61c9bc3da402).
To get appropriate vfs-like object to access files under .hg/store,
this patch adds getsvfs() (and also getvfs(), for future use).
To avoid examining existence of attribute at each repetition while
measuring performance, getsvfs() is invoked outside the function to be
called repeatedly.
This patch also adds check-perf-code.py an extra check entry to detect
direct usage of repo.(vfs|svfs|opener|sopener) in perf.py.
perf: avoid actual writing branch cache out correctly
Mercurial 2.5 (or
9b6ae29d4801) introduced "perfbranchmap" command,
and tried to avoid actual writing branch cache out by replacing
write() of branchcache class in branchmap.py with no-op function
(probably, for elimination of noisy and heavy file I/O factor).
But its implementation isn't correct, because
9b6ae29d4801 replaced
not branchmap.branchcache.write() but branchmap.write(). The latter
doesn't exist, even at that change.
To avoid actual writing branch cache out correctly, this patch
replaces branchmap.branchcache.write() with no-op function.
To detect mistake of replacement or change of API in the future
quickly, this patch uses safeattrsetter() instead of direct attribute
assignment. For similarity between replacements, this patch also
changes replacement of branchmap.read().
In this patch, replacement of read()/write() can run safely outside
"try" block, because two safeattrsetter() invocations ensure that
replacement doesn't cause exception.
FYI, the table below compares "base" filter wall time of perfbranchmap
on recent mozilla-central repo with each Mercurial version between
before and after this patch.
==== ========= =========
ver before after
==== ========= =========
2.5 18.492334 18.232455
2.6 18.733858 18.156702
2.7 18.245598 18.349210
2.8 18.289070 18.528422
2.9 17.572742 16.989655
3.0 17.406953 17.615012
3.1 17.228419 17.689805
3.2 17.862961 17.718367
3.3 2.632110 2.707960
3.4 3.285683 3.272060
3.5 3.370141 3.352176
3.6 3.366939 3.242455
3.7 3.300778 3.367328
3.8 3.300132 3.267298
3.9 3.418996 3.370265
==== ========= =========
IMHO, there is no serious overlooking performance regression.
perf: get subsettable from appropriate module for Mercurial earlier than 2.9
Before this patch, using branchmap.subsettable prevents perfbranchmap
from measuring performance of Mercurial earlier than 2.9 (or
175c6fd8cacc), because
175c6fd8cacc moved subsettable from repoview.py
to branchmap.py, even though there are some code paths for Mercurial
earlier than 2.9 in perf.py.
For example, setting "_prereadsize" attribute in perfindex() and
perfnodelookup() is effective only with hg earlier than 1.8 (or
61c9bc3da402).
To get subsettable from appropriate module, this patch examines
existence of subsettable in branchmap and repoview.
This patch also adds check-perf-code.py an extra check entry to detect
direct usage of subsettable attribute in perf.py.